Nutrients in animal feed are made available to the animal by digestion of the feed in the animal's gastrointestinal tract. Nutrients that are digested are absorbed and used by the animal for energy, growth, and development. Nutrients that are not digested, for the most part, pass through the intestinal tract of the animal decreasing the nutritional value of the feed. Digestibility of animal feed can be assessed by using in-vitro or in vivo digestion models and analyzing remaining nutrients in the digested feed by wet chemistry analytical methods. A drawback of the existing methods is that they are specific to a particular feed, expensive, and time consuming. It would, therefore, be beneficial to provide for a broadly applicable, less expensive and less time-consuming way to analyze the digestibility of animal feed.